1. Field of the Invention
The present invention relates to a method and system for quantitatively evaluating subjective inconvenience, e.g., physiological fatigue and emotional fatigue, experienced by a user when the user views a three-dimensional display screen, based on objectively measurable indices.
2. Description of the Related Art
When viewing a 3-dimensional (3D) image, a user of a 3D display system may experience inconvenience in vision, which may be crucially problematic in achieving commercialization of 3D display systems.
There are known systems for calculating a degree of ocular fatigue experienced by a 3D image display user.
When viewing a 3D image, users may experience physiological fatigue, e.g., dizziness or vomiting, as well as ocular fatigue. Thus, a variety of parameters, including the physiological fatigue, the ocular fatigue, and so on, must be taken into consideration to measure a degree of fatigue experienced by the user.
Among existing technologies for indirectly inferring a degree of 3D ocular fatigue using particular factors, Japanese Patent Laid-Open Publication No. 1997-023451 discloses a sensitivity response control apparatus detecting sensitivity information and controlling response outputs. In the disclosed patent, information about excited conditions is detected based on a temperature difference between the forehead and the nasal skin, and fatigue information is detected based on eye blinks. The intensity of a stereoscopic test pattern is adjusted based on the detection results.
Japanese Patent Laid-Open Application No. 1998-052402 discloses a visual fatigue estimation method based on presented test patterns, in which 3D image stimulations (stereoscopic eye chart) are presented with different period conditions to observe a user's visual evoked potential (VEP). In particular, according to the disclosed patent, if the user's VEP is periodically repeated, the left eye/right eye images blink. Conversely, if the user's VEP is not periodic, the left eye/right eye images are fused (combined) together. Based on the findings, the highest frequency of detecting blinks of the left eye/right eye images and the eye fatigue is inferred from the detected highest frequency (or shortest period).
Japanese Patent Laid-Open Application No. 1996-019520 discloses an eye fatigue determination technology in which movement of an eyeball is measured to generate digital data (entropy) corresponding to the eyeball movement and eye fatigue is determined if the entropy of eyeball movement representing eye fatigue increases over time.
Korean Patent Published Application No. 1999-016853 discloses a display parameter adjusting technology in which a user's papillary change is measured in a real-time basis for a predetermined period of time, a predetermined number of signals representing the user's papillary change measured for the predetermined period of time, the time-dependent papillary change applied through an image processor is analyzed based on predetermined program data, and pupil display parameters are adjusted according to a change in the area of the user's pupil.
As described above, a variety of techniques of understanding correlation between the user's particular response and eye fatigue and adjusting display parameters accordingly have been proposed. However, satisfactory techniques of quantifying the total degree of fatigue experienced by the user due to various causative parameters in the 3D image display system have not been developed.
Since the degree of fatigue applies to a 2D image display system as well as the 3D image display system, techniques for quantifying the user fatigue resulting from the use of the 3D or 2D image display system could be used as guidelines for development of the other of the 2D or 3D image display systems.